ChangeMe
Barrel Filler
Posts:1475
 | | 04/14/2004 4:27 PM |
| Hi all, my 1st post! A question about fermentation of not-dry wines. For wines like auslese mosel rieslings, where the alcohol remains pretty low and there is some residual suger, why doesn't the rest of the sugar ferment? Do the wine makers artificially halt the fermentation? If so, how (filtering yeast? chemically?).
And is a trocken auslese just an auslese where fermentation is not stopped prematurely? Just curious - I love german rieslings and just bought a bottle of karthauserhof eitelsbacher karthauserhofberg riesling auslese trocken "s" (my 1st trocken riesling - a good choice? $26 on sale) and was wondering what the difference is in making it.
Thanks.
raybanz | | | |
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DdB
Barrel Filler
Posts:1452
| | 04/14/2004 4:42 PM |
| Hi raybanz - welcome to VinoCellar!
I can't answer your question but I'm sure some of our resident Riesling experts will be along soon to expand your knowledge. | | | |
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Elizabeth Brown
Grape Fermenter
Posts:540
| | 04/14/2004 4:57 PM |
| Now i of course could be wrong and totally off base so someone please correct me - but i thought fermentation stops at a certain temp?
Good question and welcome! | | | |
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Eric White
San Ramon, CA
Advanced Sommelier
Posts:9249
| | 04/14/2004 5:38 PM |
| I sure wish Vitis still posted here, he would be the perfect person to field this question. That said, I'll add my 2 cents.
Fermentation can be halted by several factors:
- All the sugar has been converted to alcohol (completely dry)
- The alcohol reach a level where it kills the yeast (I always thought this was around 17%, but lately I've seen wines naturally fermented to 19% and heard of some above 20%!)
- Neutral spirits are added to the fermenting must (as with Port for example)
- The temperature is raised to a height where it kills off the remaning yeast
- The temperature is lowered to a point which halts fermentation
I don't know specifically for German wines, but I know many sweet wines are cooled to halt fermentation leaving natural residual sugar and I would guess that this is the method employed there also. | | | |
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ChangeMe
Master of Wine
Posts:12891
| | 04/14/2004 6:58 PM |
| welcome raybanz . i wish i could help, i just drink this overpriced grape juice  | | | |
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EricLundblad
Grape Fermenter
Posts:557
| | 04/14/2004 7:28 PM |
| I can't answer the fermentation question, but can add something on the differences between the different levels (Kabinett, Spätlese, Auslese, Beerenauslese, Trockenbeerenauslese):
Auslese wines are made from selected bunches of grapes that have been late harvested and are usually affected with botrytis (a desirable mold that concentrates sugars)
Beerenauslese wines are made from selected grapes that are almost always affected with botrytis. Note that ausleses are from selected bunches and beerenauslese are from selected grapes.
Trockenbeerenauslese wines are made from selected grapes that have botrytis and that have dried out (the grapes are left on the vine until the botrytis as consumed almost all of the grapes water and are then harvested).
The difference between the sugar levels of each of these levels is the sugar levels in the grapes at harvest, not in the finished wine (tho a beerenauslese is almost always sweeter than an auslese I believe).
Course, if GATC has anything to say on this that conflicts with what I said then I'm sure he's right and I'm wrong! | |
Ladd Cellars | |
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skwid
Wine Connoisseur
Posts:5452
| | 04/14/2004 11:41 PM |
| | Actually I don't think Auslese level wines are boytritis infected, just higher must weights. BA and TBA are boytritis infected. Eiswein is NOT boytritis infected, just frozen on the wine (at least in Germany). | | | |
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Eric White
San Ramon, CA
Advanced Sommelier
Posts:9249
| | 04/16/2004 10:02 PM |
| Ok, I got tired of no conclusive answers on this thread, so I asked an expert (Vitis!!):
First, my point #4 is false - nobody heats wine to arrest fermentation - that will ruin the wine and "turn all the alcohol into acetaldehyde" (Sherry).
"the main way fermentations are arrested in CA is they are fermented in tall narrow white fermenters with lots of jacket coverage, then they are opened fully when the correct RS is reached, then the cold flocculates the yeast, and the wine is then filtered and bottled quickly"
"although, in CA, often sweet wines are fermented dry, then concentrate is added back to hit the target RS"
Of course, I required an explaination of what "flocculate" means:
"the yeast get cold shocked and fall to the bottom of the tank in a tight layer which is easily racked off"
He wasn't sure how it is handled in Germany.
Thanks Vitis Vinifera! | | | |
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ChangeMe
Barrel Filler
Posts:1475
| | 04/17/2004 4:58 AM |
| Thanks Eric! (And thanks Vitis!)
In despair, I took the extreme step of actually looking up the answer myself
The new sotheby's wine encyclopedia (3rd ed., p. 32) says "methods that halt fermentation artificially" include:
- Heat (mmmmm, pasteurized wine)
- Cold
- Sulphur dioxide or sorbic acid
- Centrifugal filtration or filtration
- Addition of alcohol
- Pressure
- Addition of carbonic (CO2) gas
I'm guessing for hi quality unfortified wines, the only likely candidates would be cold or maybe pressure? In terms of "nobody heating wine to arrest fermentation," maybe you have to qualify that by saying "nobody who cares what their wine tastes like..."
raybanz | | | |
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ChangeMe
Grape Stomper
Posts:152
| | 04/17/2004 7:33 AM |
| Quote:
The alcohol reach a level where it kills the yeast (I always thought this was around 17%, but lately I've seen wines naturally fermented to 19% and heard of some above 20%!)
Eric, most species of yeast (Usually various forms of Saccharomyces Cerivisiae) cannot take high levels of alcohol. Should you want to ferment above 18% of alcohol, you need special strands of yeast. Unfortunately I cannot remember the name of any of these strands. ( I have known only one.)
The natural way to end fermentation is consuming all the sugar, whereafter there is no further nutrition for the yeast and the fermentation stops. Also the alcohol kills off the yeast at a certain point. The alternative is a weakening of the yeast due to the combination of both sugar and alcohol. (Sweet wines.)
There are other methods to arrest fermentation, but the above mentioned are ones in widest use.
-Increasing CO2 pressure
- reducing temperature
- removing the yeasts
- Fortification
Only the last one results in a stable wine though. | | | |
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Pool Boy
Laurl, MD (DC suburb)
Master of Wine
Posts:13711
| | 04/18/2004 10:25 PM |
| Interesting read, this thread (and thanks EW for asking Vitis!).
BTW, welcome raybanz!  | |
www.roguefood.com -- www.cellartracker.com | |
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ChangeMe
Barrel Filler
Posts:1475
| | 04/20/2004 4:06 AM |
| Thanks for the welcome tj,
If I stick around I am going to recruit you for a Baltimore Cru!
raybanz | | | |
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Pool Boy
Laurl, MD (DC suburb)
Master of Wine
Posts:13711
| | 04/20/2004 1:29 PM |
| Quote:
Thanks for the welcome tj,
If I stick around I am going to recruit you for a Baltimore Cru!
raybanz
oooooooo, a Baltimore Crü. Nice. Perhaps we can figure out the best place in Charm City to do a BYOW sometime. heh heh heh One of these days we could even do a Central Maryland Crü at Le Mannequin Pis... heh heh heh  | |
www.roguefood.com -- www.cellartracker.com | |
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juggernt
Tampa, FL, USA
Wine Bottler
Posts:3420
| | 04/21/2004 5:43 PM |
| | Raybanz: welcome! Where are you from (living)? I grew up in the Baltimore suburbs--Dundalk to be specific--although I left 20+ years ago. | |
Visit The Butcher Block at http://www.butcherblocktampa.com/ | |
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Pool Boy
Laurl, MD (DC suburb)
Master of Wine
Posts:13711
| | 04/21/2004 9:24 PM |
| Quote:
Raybanz: welcome! Where are you from (living)? I grew up in the Baltimore suburbs--Dundalk to be specific--although I left 20+ years ago.
A Dundawkian? Whoa. At least you are not an Arbutian.  | |
www.roguefood.com -- www.cellartracker.com | |
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ChangeMe
Barrel Filler
Posts:1475
| | 04/21/2004 9:30 PM |
| Thanks for the welcomes.
I am originally from East Baltimore (canton/highlandtown), and now live in northern balt. co. Lotsa family in Duldalk, though!
raybanz | | | |
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ChangeMe
Grape Stomper
Posts:199
| | 05/25/2004 3:55 PM |
| | Lets go Baltimore Cru!!! | | | |
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ChangeMe
Barrel Filler
Posts:1475
| | 05/27/2004 5:05 AM |
| Quote:
Lets go Baltimore Cru!!!
Are you in Baltimore? I'm all game for a Baltimore Cru. At the very least, I want to get the DC Cru up here once a year or so. We can BYO at restaurants w/o liquor licenses!
raybanz | | | |
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Pool Boy
Laurl, MD (DC suburb)
Master of Wine
Posts:13711
| | 05/27/2004 8:58 PM |
| Quote:
Quote:
Lets go Baltimore Cru!!!
Are you in Baltimore? I'm all game for a Baltimore Cru. At the very least, I want to get the DC Cru up here once a year or so. We can BYO at restaurants w/o liquor licenses!
raybanz
I think we could drag at least SOME of the DC Crü up that way to do one, gents. | |
www.roguefood.com -- www.cellartracker.com | |
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ChangeMe
Barrel Filler
Posts:1475
| | 05/28/2004 3:06 AM |
| Quote:
Quote:
Quote:
Lets go Baltimore Cru!!!
Are you in Baltimore? I'm all game for a Baltimore Cru. At the very least, I want to get the DC Cru up here once a year or so. We can BYO at restaurants w/o liquor licenses!
raybanz
I think we could drag at least SOME of the DC Crü up that way to do one, gents.
TJ, I'm still new here, but isn't the running joke that you don't even go to the DC events?
raybanz | | | |
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